Hi Robbie (and list folk),

    Gotcha!  The Ampico B play brake actually works the OPPOSITE way from
your description, i.e., the greatest retarding force is developed at the
BEGINNING of the roll, not the end.  The braking pneumatic is under constant
power (during play) through a #55 constriction.  The needle valve is teed
into the pneumatic and admits a continuously increasing amount of atmospheric
leakage into the pneumatic as the supply spool diameter decreases, thereby
decreasing the pneumatic's braking force.  This is from the service manual
but you can perform a simple confirming test:  Put a suction tube on the
needle valve connection at the back of the drawer, draw on it and depress
the paper follower lever to the bottom of the drawer.  This is the condition
when a full supply spool is present.  Notice that there is almost no leakage
or flow through the needle valve, therefore, the pneumatic will develop it's
maximum (retarding) force.  Now, begin to allow the paper follower to rise
and notice that the flow through the needle valve begins to increase, thereby
decreasing the pneumatic's power.

    Think about it this way:  We can all agree (I think) that paper "skidding"
occurs when high paper retarding forces (mostly due to the vacuum at the
tracker bar) bring the paper to a halt until the loose turns of paper on the
takeup spool tighten enough to overcome the retarding force.  ADDITIONAL
retarding force (from the play brake) toward the end of the roll is just what
you DON'T need!

    There have been many discussions in past years in the AMICA bulletin and
similar publications.  I seem to recall someone (whom I do not recall)
advocating "lightly" sanding the edges of the paper with fine sandpaper to
give it some "tooth".  I have never personally tried this, but it makes
engineering sense to me, although it sounds fairly labor intensive.  Probably
best to reserve the technique to recuts, which, because of the slickness of
many modern papers being used for the purpose, seem to exhibit the problem
more often anyhow.

Regards to all.  -John Grant